| 年度 | 实际值 |
|---|---|
| 1992 | 37.2 |
| 1993 | |
| 1994 | |
| 1995 | 37.8 |
| 1996 | |
| 1997 | |
| 1998 | |
| 1999 | 39.4322 |
| 2000 | 39.4698 |
| 2001 | 38.992 |
| 2002 | 39.0286 |
| 2003 | 39.54 |
| 2004 | 39.7401 |
| 2005 | 39.3732 |
| 2006 | 39.8149 |
| 2007 | 40.1697 |
| 2008 | 40.2543 |
| 2009 | 40.6457 |
| 2010 | 40.6302 |
| 2011 | 40.7916 |
| 2012 | 40.3821 |
| 2013 | 40.5657 |
| 2014 | 40.8563 |
| 2015 | 40.8894 |
| 2016 | 41 |
| 2017 | 40 |